Four face recognition programs match Youssef’s photo to all these photos of Ramzi-bin-al-Shibh, a Yemeni national held in Guantanamo Bay prison since 2002. Ramzi is accused of being an al Qaeda operative and a "key facilitator for the September 11th attacks". He is sometimes referred to as the ‘20th hijacker’. I have been told by one experienced face recognition professional that they are not the same person but they are likely to be related.